Numerous combinations of reagents that have beneficial or desirable characteristics can lose their desirable properties over time. This transition can be prevented by maintaining each component separately prior to use, e.g., until their combined function is desired. Examples of these combinations include reagent aggregation in solution, reagent degradation, production of gases that alter the concentration or physical properties of the solution, and changes in pH, color, taste of regent in solution.
An additional problem associated with combining dry and wet reagents within a closed housing is the difficulty in ensuring that the reagents are completely dissolved. Manipulation is usually required to ensure that the dry reagent is exposed to the diluent. The potential for incomplete dissolution is increased by the need for agitation. The duration and degree of agitation is directly proportional to the degree of dry reagent dissolution. Without adequate agitation, dry reagents may not be completely dissolved and the resulting solution would have the desired characteristics.
The difficulty associated with achieving complete dissolution of reagent is more difficult when a small volume of diluent is used to dissolve a large volume amount of dry reagent. The preparation of certain solutions is particularly difficult with combinations that use small volumes of diluent compared to the dry reagent volume. Examples of these types of combinations include vaccines, biotechnology derived drugs and concentrates of any form. This problem is also difficult with poorly soluble reagents.
With some combinations of reagents, excessive agitation produces undesirable characteristics. For example, protein-containing solutions produce foaming with excessive agitation. Foaming of protein solutions can lead to protein denaturation, which can destroy the activity of the protein solution. Additionally, foaming can prevent complete delivery of the solution from the preparation container as some portion of the foam will frequently remain in the vessel used for agitation.
Methods used to combine wet and dry reagents include containment of reagents in separate containers that are joined together, then the separation is removed and the reagents are combined by vigorous agitation of the combined containers. Other attempts to prepare a solution from separated components include containment of the components separately within a single packaging. These include containment of diluent within a bag that has a breakable barrier or perforation mechanism that allows contact of the separated reagents.
For these and other reasons, apparatus and methods for dissolving and mixing reagents rapidly, efficiently, and with minimal agitation would be desirable.